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This paper presents the inclusion of new, relevant impact categories for agriculture life cycle assessments. We performed a specific case study with a focus on the applicability of spatially explicit characterization factors. The main goals were to provide a detailed evaluation of these new impact category methods, compare the results with commonly used methods (ReCiPe and USEtox) and demonstrate how these new methods can help improve environmental assessment in agriculture. As an overall conclusion, the newly developed impact categories helped fill the most important gaps related to land use, water consumption, pesticide toxicity, and nontoxic emissions linked to fertilizer use. We also found that including biodiversity damage due to land use and the effect of water consumption on wetlands represented a scientific advance toward more realistic environmental assessment of agricultural practices. Likewise, the dynamic crop model for assessing human toxicity from pesticide residue in food can lead to better practice in pesticide application. In further life cycle assessment (LCA) method developments, common end point units and normalization units should be agreed upon to make it possible to compare different impacts and methods. In addition, the application of site-specific characterization factors allowed us to be more accurate regarding inventory data and to identify precisely where background flows acquire high relevance.

The agri-food sector has moved towards a more linear production economy, partly caused by worldwide food demand. One clear example is the intensification of livestock production, with consequent manure-management and feed-production challenges, the effects of which have led to large environmental problems. Currently, efforts are being made to move the agricultural sector towards closed-loop alternatives. To ensure high environmental performance of these alternatives, realistic quantification of environmental impacts is needed. Thus, using Life Cycle Assessment (LCA) tools, we analyzed the environmental profile of six closed-loop maize scenarios focusing on different combinations of mineral fertilizer, digested organic fertilizer (digestate) from a manure co-digestion biogas plant, and rotation with (or without) catch crops (CCs) as a strategy to prevent nitrate leaching to groundwater and as a co-substrate in the biogas plant.Results demonstrated that replacing a large portion of the mineral fertilizers with digestate could help offset much of the total potential impact of global warming (by 25-35 %), resource depletion (by 94-96%), photochemical ozone formation (by 17-22 %), ozone depletion (by 96-99%) or even avoid it entirely as in freshwater eutrophication. However, digestate production and application contributed greatly to acidification (51%) and particulate matter (51-52%) categories, with minor differences depending on the species of CC used. An optimal combination of both digestate and mineral fertilizers is recommended. The incorporation of CCs in a maize rotation can reduce freshwater eutrophication impacts but increase global warming potential. Conclusions were drawn suggesting better management strategies to decrease environmental impacts of maize production.

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8Purpose: Previous studies have shown the importance of including agricultural capital goods in 9 environmental assessments. In particular for protected crops, greenhouse structural components 10 may account for nearly 30% of the total in environmental impact categories such as resource 11 depletion and global warming. The lack of appropriate datasets can make it difficult to include 12 these structural components. The present paper provides a modelling approach for the greenhouse 13 inventory stage to provide better assessments of greenhouse production systems. 14 Methods: In this study, four main greenhouse structures were assessed: a glass greenhouse, a 15 multi-tunnel greenhouse, a local Mediterranean type known as the parral greenhouse and a low-16 tunnel greenhouse. After selecting the main materials of the structure, we generated equations to 17 calculate the amount of the main structural materials as a function of the main greenhouse 18 dimensions. We performed a quality assessment of the data used for different greenhouse 19 structures. We also calculated a simplified environmental assessment made by the different 20 structures to the climate change category in order to test the effects of the different amounts of 21 material in the four greenhouse types. 22Results: Equations to calculate the amount of the main greenhouse materials as a function of 23 greenhouse size are provided. For the four greenhouse types under consideration, statistical 24 correlations showed a good fit between the amounts of greenhouse materials and the parameters 25 related to the main greenhouse dimensions, such as greenhouse perimeter, surface and volume. 26The results from the complementary impact assessment study show that glass greenhouses 27 contributed the most in the climate change category, with an average value of 2.9 kg CO 2 eq·m -2 . 28After variability was taken into account, multi-tunnel and parral greenhouses showed similar 29 2 values of between 0.6 to 1.2 kg CO 2 eq·m -2 , while low-tunnel greenhouses had the lowest ranges, 30 between 0.45 and 0.53 kg CO 2 eq·m -2 . The environmental assessment was done using the square 31 metre as a reference flow, so the actual impact depends on the functional unit selected, which is 32 usually the yield. 33Conclusions: Application of the equations developed in this study provides an easy way to 34 calculate the quantity of materials used to make greenhouses of different dimensions, thus 35 resulting in more accurate calculation of greenhouse production system impacts. This analysis also 36 highlights the importance of the different amounts of materials used to build these structures and, 37 therefore, the need to include ranges of uncertainty in environmental analyses. 38

In intensive livestock production areas, farmers must apply manure management systems to comply with governmental regulations. Biogas plants, as a source of renewable energy, have the potential to reduce environmental impacts comparing with other manure management practices. Nevertheless, manure processing at biogas plants also incurs in non-desired gas emissions that should be considered. At present, available emission calculation methods cover partially emissions produced at a biogas plant, with establish which methodology is more reliable. Therefore, more measurements at different biogas plants should be evaluated to validate the methodologies more precisely.